Thermostat.



F. KUHN & P. E. SHAILOR. THERMOSTAT. APPLICATION FILED D110. 2, 190s" 1,107,3-1 6, Patented Aug. 18, 1914.

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E'RANIIv KUHN AND ERANH' E. sHAILoR, lor DETROIT, MICHIGAN, AssIeNoRs To AMERICAN ELECTRICAL HEATER COMPANY, or DETROIT, MICHIGAN, A CoRroRA- f 'TIoN or MICHIGAN.

T0 allwhom t'may concern:

Be it known that we, FRANK KUHN andl FRANK E. SHAILOE, citizens of the United States of America, residing at Detroit, .inv

the county of Wayne and State ofcMichigan,t

have invented-certain new and useful Im-l easily .disarranged parts, and positive in its operation. To this end, the inventio-n consists', first,

in the,` construction of mechanism havinga thermostatically-controlled friction look; further, in the peculiar construction, arrangement and combination of parts, as hereinafter set forth.

In the drawings-Figure l is a plan view of the thermostat as applied for controlling 1 an electric switch; Fig. 2 is a Similar view'. showing the switch in tripped position; Fig.

3 illustrates the application of the thermostat to an electrically-heated sad iron; Figli is a longitudinal section through` the rotary member and brake.

In the present state of the art thermostats have been found unsatisfactory for use yin any place where positive and certain operation is required, and without attention and adJustment. The defect is generally due to the fact that the movement of the thermostatic member, under variations in temperature, 1s slight, and where its movement is magnified by any system of leverage the connection is variable and uncertain. It is one of the objects of the present invention to obtain a positive and complete control by a very slight movement of the thermostatic or expansible member. This I have accomplished by the construction of a `friction rake for normally holding the movable member of the mechanism from operation, 'raid brake being released by a microscopic movement, due to the thermostat.

In the specific construction, A is a rotary member, mounted upon a stationary member B. n

C C are conical and relatively movable i brake shoes engaging the opposite ends of the member A. These shoes are clamped between the opposite ends D and E of the thermostatic member which, as shown, is

y l'Specification p1 Letters Patent. Application'led December 2, 1909. A Serial No. 531,102.

. THERMOSTAT.

Patented Aug. 18, 1,914.l

i formed of a Ui-'shaped metallic bar F,ihaving a bar G of a different metal with a higher coefficient of expansion arranged between the legs thereof. The rotary member Al is preferably provided with a series of ratchet= teeth for engagement with a dog orrpawl H upon a member I of an electric switch. This member I, as shown, is secured toa'rotary shank J, having an operating button K at 'its upper end, and a spring L coiled thereon for exerting a rotative tension sufficient to throw j the switch. In the normal position ,of the' parts, the pawl H is engaged with one of ,the ratchet teeth of the member A and is held thereby against the tension of the s ring .L in Contact with the cooperating e ectric Contact M of the switch.

In operation, whenever there is'a rise in temperature ysufficient to cause an expansion of the bar G, this will cause a very slight spreading of the legs D and E of the U- .shaped bar F, with the result that pressure on the friction shoes C and C is released, and this results in pressure upon the member A. This will permit the tension of the spring L to rotate the shank J', revolving the member A to disengage the dog H and permitting the contact I to separate from the cooperating contact M. To adjust or set the instrument, ar member M, having a threaded shank O is preferably arranged intermediate one of the legs E and the friction shoe C. By turning the threaded shank the pressure on the shoe C may be altered, and when once adjustedthe parts "are rigidly locked by a nut I. v

This construction of thermostat is particularly applicable to electrically-heated sad irons, as illustrated in Fig. 3. In this construction, the member F is bolted directly to the heating unit, and the thermostat is set so that the normal heating of the iron will not release the switch, but any rise in temperature above normal, even if only a few degrees, will release the brake, and permit the automatic cut-olif of the switch. V,

To avoid danger of a slow opening of the switch, the contact member I is preferably attached to the member I, so as to have a slight lost motion thereon. Thus, when the member I is first released, it will permit a certain amount of movement before separatingl the contact I from the cooperating contact M. y

What wel cla-im as our invention is:

1. A'thermostat, comprising a movable member, a friction lock for said member, and means operating upon avariation in temperature for releasing said lock.

2. A thermostat, comprising an automatically-movable member, a friction lock for holding said member, and means operated upon a change in temperature for releasing said lock.

3. A thermostat, comprising an automati-l cally-movable member, a friction shoe bearing upon said member, and an expansible membernormally holding said shoe in locking engagement with said movable member adapted to release the same at a predeter mined temperature variation.

4.' A thermostat comprising a rotary member, friction shoes engaging opposite sides of said member, lan 4eipansible member normally clamping said shoes but adapted to release the same upon rise in temperature i to a predetermined point, and an automatiriot/,aie

6. A thermostat, comprising an automatically-operated member, a rotary ratchet member, a pawl on the movable member of said automatically operated member engageable with said ratchet member, a friction shoe bearing on said ratchet member, a U-shaped expansible thermostatic member embracingnsaid rotary ratchet member and shoe and normally clamping the same together. p

7. A thermostat comprising a U-shaped member, a member having a greater co-eiiicient of, expansion extending between the legs of the U, a rotary member embraced by said U-shaped member, afriction shoe bearing on the end of said rotary member, and an adjustable member between said friction shoe and one leg of said U-shaped member, for the purpose described.

8. A thermostat comprising a rotatable member, a friction lock` for holding said member from' rotation, means operating upon a change in temperature for releasing said lock, and anautomatically movable member normally held from movement by engagement with said rotary member.

ln testimony whereof we affix our signatures in presence of two witnesses.

FRANK KUHN. FRANK l1; SHAILOR.

Witnesses:

HENRY F. KOLBE, GEORGE S. TOWAR. 

